1. Field of the Invention
The present invention relates to a technique for dynamically classifying data using metadata attached to the data.
2. Description of the Related Art
Techniques in which data is automatically classified on the basis of metadata attached to the data have been proposed. For example, Japanese Patent Laid-Open No. 2000-250798 discloses a method in which a folder is generated for each value of a metadata item that is selected by a user and in which data elements having the corresponding value of metadata are stored in the folder to perform classification based on the values of metadata. The disclosed method allows layered classification according to preferences of a user by specifying the order of use of metadata items during the classification, and provides various folder systems, which are not feasible with existing folder management techniques.
In the related art, however, since a number of folders corresponding to the number of values of metadata are generated, a large number of folders are generated in order to classify a large number of data elements. It is therefore difficult to apply this method to compact devices with limited screen sizes. Further, unlike the storage of data in static folders, a search based on a metadata item is performed every time a folder containing classification results is opened. In order to improve performance, for example, data elements classified in an unopened folder are read ahead and cached in a memory. However, compact devices with limited memory capacities do not have sufficient cache space, and have a problem with performance.